Head and a cutting insert for a reaming tool and reaming tool with such a head and insert

摘要

The invention relates to a reaming tool that includes a head (2) and one or more detachable cutting inserts (3) that are fixed in seats (17) in the head. The seat includes a radial support surface (18), a tangential support surface (19) and an axial support surface (20), while the cutting insert has the shape of a mirror-symmetrical polyhedron comprising six limiting surfaces (29,30), viz. two chip surfaces (29) and four clearance surfaces (30), a number of alternately usable identical cutting edges (33) being formed in the transitions between the chip and clearance surfaces. According to the invention, the cutting insert has (3) a rhombic cross-sectional shape and includes four clearance surfaces (30), which meet each other in pairs at obtuse angles in two opposite corners (31), and which, along each individual chip surface (29), form two cutting edges (33) alternately usable by the indexing of the cutting insert, the seat (17), in addition to the radial and tangential support surfaces (18,19), including a slope surface (22) that forms an obtuse angle with the radial support surface (18), suitably of the same magnitude as the obtuse angle between the clearance surfaces (30) of the cutting insert. In addition, the invention relates to a tool head and a reaming insert, respectively, for the present tool.